[Scummvm-devel] GZip savegames

Max Horn max at quendi.de
Mon Dec 1 10:52:19 CET 2003


Yo,

as you may have noticed, I recently commited code which allows for 
storing savegames compressed. Engines which use SaveFileManager (and 
all engines should do that... I hope all do it, indeed :-) get the 
ability for free. All you have to do is to define USE_ZLIB when 
compiling ScummVM (and of course you need to have zlib, and link 
against it, i.e. on Unix add a -lz). Old uncompressed savegames can 
still be loaded. New savegames (for scumm) are typically reduced by a 
factor 2-7 in my tests.

Note:
* zlib is very well tested and has very good performance (including low 
memory usage)
* zlib is portable to almost everything out there, I dare to say to far 
more systems than ScummVM runs on at this time
* going "back" wouldn't be a problem: if you want to send a compressed 
savegame to somebody with a ScummVM w/o compression support, just use 
"gunzip" to decompress the savegame
* speed is no issue. Memory shouldn't be an issue either

Personally, I think we should make zlib a requirement for compiling 
ScummVM, and just always use it. This way, nobody should ever have to 
manually decompress savegames. And virtually every Unix comes with zlib 
pre-installed.

In the meantime, anybody can try out the code as described above


Cheers,

Max





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